The present invention generally relates to a two-part digging tooth system and, more specifically, to a hammerless attachment assembly for releasably maintaining an adapter and a replacement part of a two-part tooth system in operable combination relative to each other.
Excavating equipment used in mining, construction and a myriad of other ground engaging operations typically includes a series of spaced apart ground engaging tools or teeth arranged in side-by-side relation across a bucket lip or blade. The digging teeth project forwardly and serve to break up material to be gathered into a bucket of such excavating equipment.
The art recognized long ago the advantages to be gained by constructing each digging tooth as a two-part system. That is, the art recognized the advantages to be obtained by connecting a ground engaging tooth or tool to an adapter or support which, in turn, is connected to the bucket of excavating equipment. Typically, the adapter or support is provided with a base portion which is configured for attachment to the forward lip or blade of a bucket and a free ended nose portion. The digging tool is typically provided with a blind cavity or pocket whereby allowing the tool to fit over and along the adapter nose portion. As will be appreciated by those skilled in the art, the size of the adapter and digging tooth vary depending upon the particular digging application. For example, a two-part digging tooth system can vary in weight between a few pounds, i.e., three to five pounds, to two-hundred pounds.
During some digging operations, such teeth assemblies are subjected to highly abrasive conditions and, thus, experience considerable and rapid wear. Unless the conjuncture between the component parts of the two-part system is properly fitted, wear problems, especially in the pocket or cavity of the replacement part and along the nose portion of the adapter, can result. Moreover, the relatively high forces developed during some digging operations furthermore add to the rapid wear of the component parts of the digging tooth assembly.
In service, and although specific steps may be taken during fabrication of the digging teeth, a forward cutting edge of the replacement part sometimes quickly wears and become dull and, thus, inefficiencies in the digging operation develop thereby requiring replacement of such parts. As mentioned, the multipiece or two-part construction of such a tooth assembly advantageously allows the digging or excavating tooth to be replaced independent of the adapter. Depending upon conditions, a given adapter can be successfully equipped with anywhere from five to thirty replacement digging teeth to maintain sharp penetrating edges. In the field, replacement of worn excavating or digging teeth is a common and sometimes a daily experience.
It is well known in the industry to releasably interconnect the component parts of the two-component parts with an elongated retaining pin. Removing the replacement part from the digging system component parts, however, involves a tedious and often difficult task of pounding the retaining pin from registering apertures in the replacement part and the adapter. Removal of the retaining pin is typically effected by using a large hammer to manually and endwise force the retaining pin from the apertures in the digging tooth and adapter. Of course, with larger two-part digging systems, the retaining pins are proportionately sized larger thereby adding to the manual effort and, thus, increasing the time and effort involved to effect digging tooth replacement and/or repair. Problems involving the hammer missing the punch or other tool used to removably pound the retaining pin and hitting the hand of the operator are well known. Of course, similar problems exist when the retaining pin is again pounded into the apertures to effect reattachment of the replaceable part and the adapter. The availability of appropriate tools, i.e., hammers and punches, is a consistent and well known problem.
Many two part digging systems arrange the retaining pin along a generally horizontal axis. As will be appreciated by those skilled in the art, with the digging systems being mounted in side-by-side relation relative to each other across the bucket lip, the horizontal disposition of the retainer pin for each digging system only adds to the time and effort required to initially remove the pin, whereby allowing for removal/repair of the worn/broken part of the digging system and, subsequently, reinsertion of the pin into the registered apertures in the replacement part and adapter of the two-part system. Some operators utilize specially designed tools to facilitate removal of the horizontal pins. Of course, availability of such tools is another problem.
It is also known to arrange the retaining pin in a generally vertical orientation. While advantageously enhancing access to the retaining pin, such retaining devices are more susceptible to the forces applied thereto as a result of the generally vertical movements of the bucket during a digging/excavating operation. Moreover, with a vertically oriented pin system, the lower hole or aperture in the replacement part of the two-part digging system is more exposedxe2x80x94as compared to a horizontal pinning systemxe2x80x94to the ground surface over which the digging implement or bucket moves during a digging operation.
In any digging or excavating operation, contaminants including rocks, dust, dirt fines, moisture, and etc. furthermore exacerbate removal of the retaining pin. During any digging or excavating operation, small rocks, stones, dirt, dirt fines, and dust quickly accumulate, fill, and pack into holes or apertures in the digging tooth and adapter. As will be appreciated, moisture readily and quickly moves between confronting surfaces formed at the conjuncture of the digging tooth and adapter and passes toward the retaining pin. As is well known, the moisture corrodes and rusts on the surfaces of both the retainer pin and closed margins of the apertures in the digging tooth and adapter thereby adding to the problem of retaining pin removal. Moreover, such moisture often combines with the small rocks, stones, dirt, dirt fines, and dust already packed and filled into the apertures or holes of the component parts of the two-part tooth system, thereby adding to the considerable labor already involved with effecting tooth replacement.
Using threaded devices for releasably interconnecting component parts of a two-part tooth system have been previously proposed. For example, U.S. Pat. Nos. 5,337,495 and 6,052,927 to S. Pippins disclose an externally threaded tooth point bolt in combination with an insert for releasably maintaining a digging tooth and adapter in operable combination relative to each other. Like others before, the Pippins devices do not solve the problem of having contaminants including small rocks, stones, dirt, dirt fines, dust, and moisture passing into the apertures and onto both internal and external threads of the interconnecting devices thereby resulting in clogging, oxidation and corrosion of the mating surfaces. Of course, contamination of any mating threaded surfaces as by clogging, oxidation or rusting can only further add to the problems of disconnecting the related parts relative to each other when servicing of the worn part of the two-part system, is required. Moreover, the Pippins devices fail to disclose any means for inhibiting wear between the component parts of a two-part digging tooth system.
Thus, there is a desire and a continuing need for a hammerless attachment assembly for releasably maintaining component parts of a two-part digging tooth system in operable combination relative to each other. There is also a continuing need and desire for a two-part tooth system having an attachment assembly which enhances the conjuncture between the component parts of the system thereby reducing wear between the parts.
In view of the above, and in accordance with one aspect of the present invention, there is provided a hammerless attachment assembly for releasably maintaining component parts of a two-part digging tooth system in operable combination relative to each other. The component parts of the tooth system include an adapter having a nose portion with multiple sides and a ground engaging tool defining an open ended blind cavity or pocket for allowing the tool to fit over and along a length of the adapter nose portion.
The hammerless attachment assembly of the present invention includes an insert nonrotatably fitted within a recess defined on a side of the nose portion of the adapter and a rotatable fastener having a head portion and an externally threaded shank portion. A lengthwise portion of the fastener extends through an opening having a closed margin defined in a side of the tool, with the opening in the side of said tool registering with the internally threaded bore in said insert when the tool is positioned on the nose portion of the adapter. To releasably fasten the tool and adapter in operable combination relative to each other, the externally threaded shank portion of the fastener forms a threaded juncture with the internally threaded bore on the insert such that, in response to rotation of the fastener in a first direction, the insert is drawn toward and, ultimately, moved into clamping relation with an interior side surface of said blind cavity while remaining, at least partially, within the recess in the adapter thereby releasably maintaining the tool and adapter in operable combination relative to each other.
According to one aspect of the invention, elastomeric material is disposed in operable combination with the rotatable fastener and the insert for inhibiting contaminants from adversely effecting the threaded juncture between the fastener and the insert. As will be appreciated by those skilled in the art, inhibiting contaminants from adversely effecting the threaded juncture between the fastener and the insert will facilitate rotation of the fastener in a direction opposed to said first direction when the tool is to be released from operable combination with the adapter.
In one form, the elastomeric material extends along the entire lengthwise section of the externally threaded shank portion of the fastener extending through the insert. In another form, elastomeric material is configured as part of the insert and defines the internally threaded bore for the insert. In this form, the elastomeric material has an exterior configuration which inhibits separation of the elastomeric material from the insert as the insert is drawn toward and ultimately moved into clamping relation with the interior side surface of said blind cavity defined by the tool.
The insert preferably includes inner and outer surfaces. The insert""s inner surface faces the adapter and the outer surface of the insert is arranged adjacent the interior side surface of the blind cavity after the fastener is rotated to draw the insert into clamping relationship therewith. Alternatively, the insert can embody a two-piece construction with a first piece or part defining the internally threaded bore and the second part or piece being arranged in operable engagement with the first part when the insert is inserted into the recess in the side surface of the adapter. According to still another aspect of the invention, the insert is formed from a non-ferrous material. Accordingly, moisture passing between the parts of the digging system will have limited, if any, adverse effect on the threaded juncture established between the insert and the threaded fastener.
In yet another embodiment, and in response to the insert being clamped against the interior surface of the tooth cavity, elastomeric material is squeezed between insert and the interior surface of the tooth cavity. In this form, elastomeric material furthermore extends, at least partially, into operable surrounding relation with the externally threaded shank portion of said fastener thereby inhibiting contaminants from getting through to the threaded juncture between the fastener and the insert. As such, the threaded juncture is sealed against contaminants interfering with proper and efficient operation between the fastener and insert of the retainer assembly.
As will be appreciated by those skilled in the art, the nose portion of the adapter and the blind cavity or pocket defined by the tool have complimentary cross-sections. In a preferred form, at least a top surface of the nose portion of the adapter is configured with two angled sides disposed on opposed lateral sides of a longitudinal centerline of the adapter. Similarly, the blind cavity defined by the tool opens to a rear end of the tool and includes a top surface having two angled sides disposed on opposed lateral sides of the longitudinal centerline of the tool and are complimentary relative to the angle sides on the top surface of the adapter.
The angled configuration of the sides on the nose portion of the adapter and tool cavity provide advantages over other cross-sectional configurations at the conjuncture between the tool and adapter. For example, the angled sides on the adapter and cavity advantageously provide a larger bearing surface at the conjuncture between the adapter and tool than is offered by horizontally configured surfaces. Of course, a larger bearing surface yields enhanced load distribution of the forces imparted to those surfaces. Moreover, the angled side configuration on the adapter and cavity advantageously provide a self-centering effect at the conjuncture between the tool and the adapter.
In this regard, both the insert accommodating recess in the side of the adapter and the insert are preferably configured to enhance the self-centering effect between the tool and the adapter on which it is mounted. More specifically, the recess defined in the side of the adapter and the insert are preferably configured with complimentary surfaces which cooperate relative to each other to enhance the self-centering effect at the conjuncture between the tool and adapter. Moreover, when the top surface of the adapter is configured with angled sides, the open top insert accommodating recess in the side of the adapter defines an axis extending generally normal to the side surface of the adapter to which the recess opens.
Another aspect of the present invention relates to the ability of the attachment assembly to enhance the conjuncture between the adapter and tool by urging to the tool onto the nose portion of the adapter in response to the fastener being rotated in a direction to tighten the clamping relationship of the insert against the interior surface of the blind cavity defined by the tool. To effect such ends, the rotatable fastener of the attachment assembly includes a portion for engaging a closed margin of the opening in the side of the replacement part through which the fastener extends. Moreover, the insert and the insert accommodating recess on the nose portion of the adapter define confronting surfaces which cooperate relative to each other as the insert is drawn toward the interior surface of the cavity, in response to rotation of the fastener. The confronting surfaces cause the insert and, ultimately, the replacement part to move rearward in a direction extending generally parallel to the longitudinal axis of the adapter thereby enhancing the tightness of the conjuncture between the interior surfaces of the blind cavity and the nose portion of the adapter.
A primary object of the present invention is to provide an improved attachment assembly for releasably maintaining a replacement part and an adapter of a two-part digging system in operable combination relative to each other.
A further object of the present invention is to provide a hammerless attachment assembly for a two-part digging system including a replacement part and an adapter and which offers enhanced ease of repair/replacement of the replacement part, when required, during a digging operation.
Another object of the present invention involves providing a hammerless attachment assembly for a two-part digging system including a replacement part and an adapter and wherein the two-parts of the digging system are maintained in operable combination relative to each other through a fastener forming a threaded juncture with an insert arranged in a recess on the adapter and wherein elastomeric material inhibits contaminants, inherent with digging environments, from adversely effecting the threaded juncture thereby promoting release of the fastener from the insert, when required, and, thus, enhancing replacement of worn parts of the two-part digging system.
Still another object of the present invention is to provide a hammerless attachment assembly for releasably maintaining a replacement part and an adapter of a two-part digging system in operable combination relative to each other and wherein the attachment assembly includes a rotatable fastener which enhances the conjuncture between the replacement part and the adapter in response to rotation of the fastener in a direction to releasably fasten the replacement part to the adapter.
These and other numerous objects, aims, and advantages of the present invention will become readily apparent from the following detailed description, drawings, and appended claims.